Rotary ductor mechanism



Feb. 11, 1958 R. WOESSNER ETAL 2,822,753

ROTARY DUCTOR MECHANISM Filed Sept. 21, 1956 INVENTOR 2 AT iORNE $5, 7 I

United States Patent ROTARY DUCTOR MECHANISM Richard Woessner, Fair Lawn, N. J and Albert T. Zurick,

York, Pa., assignors to R. Hoe & Co., Inc., a corporation of New York Application September 21, 1956, Serial No. 611,307

4 Claims. (Cl. 101--350) This invention relates to improvements in ductor mechanisms in printing machine ink motions. More particularly, the invention relates to that class of such mechanisms in which a ductor roller, which conveys the ink from the fountain roller to the first ink drum of an ink motion, is given a movement of revolution about a center repeatedly describing the path of movement in the same direction, as opposed to the more familiar type of movement, in which the ductor roller swings back and forth in an oscillating movement, between the fountain roller and ink drum.

It is known practice to mount a ductor roller on a rotary member and to modify its path of movement out of a true circle as may be required for obtaining proper contact successively with the fountain roller and the ink drum, or to mount it resiliently, for the same object, or to provide a roller travelling in a generally hypocycloidal path.

The present invention relates to ductor roller mechanisms of the type last mentioned and has for its general objects the obtaining of improved contact between the ductor roller and the members it engages, and improvements in the mounting and dimensioning of parts, to provide a more efficient path of movement.

A rotary ductor mechanism embodying the invention in a preferred form will now first be described with reference to the accompanying drawings, and the features forming the invention will then be pointed out in the ap pended claims.

In the drawings:

Fig. 1 is a somewhat schematic side elevation of an ink motion embodying the invention in a preferred form; and

Fig. 2 is a section on a somewhat larger scale, on the line 22 of Fig. 1.

Fig. 3 is a view of the ductor roller adjusting mechanism as indicated by arrow 3 in Fig. 2.

Referring now to Fig. 1, there is there shown a first drum of an ink motion, which, as will be understood, may contain a variety of other drums and rollers beyond that shown, and ultimately applies ink to plates on a form cylinder. Associated with this drum for inking the same are an ink fountain 11, a fountain roller 12 and a pair of doctor rollers 13 supported by a mechanism operating within an annular member 14, to carry the ductor rollers in a looped hypotrochoidal path 15, as indicated.

The roller carrying mechanism has a shaft toward the ends of which are mounted discs 21, and this shaft is driven by a gear 22. Shafts 23, one of which is shown in Fig. 2, are rotatably supported in the discs 21 by means of anti-friction bearings 24. At one end of each shaft 23 and fixed thereto, is an arm 25 supporting an anti-friction roller bearing 26 in which a ductor roller 13, provided with the usual soft surface 27, is journaled. At the other end of each shaft 23, there is mounted a planetary spur gear 28, which is fixed to the shaft 23 and has teeth meshing with internal ring gear teeth 29 formed on the annular member 14 which is secured by means of bolts 30 to the outside of the ink motion frame structure 31. A ring 32 closes the opening between the periphery of the disc 21 and the annular member 14.

The shaft 20 is supported in bearings 33 carried in a frame member 34, secured to the ink motion frame 31. By reason of the engagement of spur gears 28 with the ring gear 29, shafts 23 are caused to rotate on their own axes as the discs 21 rotate, imparting to rollers 13 a hypotrochoidal path 15, as indicated. It will be observed that this path includes four loops 15' and four concave sections 15 between the loops. The curvature of the concave sections may be selected so as to approximate quite closely the shape of an are about the ink drum 10, although diverging from a true concentric path at each loop. This path may be chosen by suitable selection of the distance of the shaft 23 from shaft 20, and the length of arm 25 so as to produce an ideal condition as to the extent of compression of the soft surface 21 of the roller 13. The ink fountain is positioned so as to obtain a suitable relationship between the fountain roller 12 and the ductors 13, thus producing an ideal arrangement.

While it has previously been attempted to utilize a hypocycloidal motion of a ductor roller, with the supporting parts rotating at uniform speeds, the time of contactand condition of contact as between the ductor roller and the cooperating fountain roller and ink cylinder have not been entirely satisfactory due to the limited time of contact and the abruptness of establishing of contact. As will be apparent, when the ductor roller approaches the ink drum 10 along a path which is very close to being concentric, its acceleration may be more gradual and the inking be more even, since ink is wiped off on the roller (which is itself free to rotate) in a much smoother and more uniform manner than heretofore, due to the rotation of the fountain roller and the ductor roller together, and also the movement of the fountain roller along a path approximating, but not following exactly, ooncentricity about the fountain roller axis. Similarly, the ductor roller is gradually accelerated as it is brought gradually into contact with the first ink drum and is smoothly accelerated without sudden jumps and starting movements, so that the ink on the ductor roller is smoothly and evenly transferred through a considerable arc of the ink drum, requiring much less smoothing out and working thereafter than has heretofore been the case. It has been found that an arc of contact, or rather effective ink transferring relation, between fountain roller and ductor roller, and between ductor roller and ink drum, subtending an angle of about 20 on the ink drum 10, produces the desired action in most cases. However the proportions of the parts may be varied so as to vary this angle within a range from about 10 of angle, to about 40 of angle, to suit particular conditions.

What is claimedis:

1. In a printing machine ink motion having a fountain roller and a train of ink motion rollers including a first ink drum, the combination with the ink drum and fountain roller of ductor roller mechanism for transferring ink from the fountain roller to the ink drum, and comprising a rotary support, bearings supporting the same between fountain roller and ink drum, a pair of ductor roller supporting shafts rotatably journaled in the said support eccentrically to its axis of rotation and opposite each other with respect to the said axis, a spur gear carried by each said shaft at one end thereof and a roller supporting arm carried by each said shaft at the other end thereof, bearings at the ends of said arms supporting a pair of ductor rollers, an internal ring gear and means mounting it for engagement with the said spur gears, whereby a hypotrochoidal path of movement is imparted to the ductor rollers as the rotary support rotates, the di mensions of the parts being such that the said path of Patented Feb. 11, 1958.

movement comprises four-concave sections with loops between them, oneof the said concave sections being nearly concentric with an adjacent ink drum and another concave section being nearly concentric with the axis of the fountain roller. 7

2; The combination according to cla'irnl, in which the radius of the said roller supportingarmsissubstantiaIly equalto the roller radius, the shafts-carrying the said roller supporting arms are located ata distance from the rotary support axis substantially equalto the said supporting arm radius increased by the roller radius and the rotary support shaft radius, and the said spur gears have pitch-radii less than the-said roller supporting arm radii whereby the centers of the rollers trace a hypotrochoidalpathwhich approaches a circular arc concentric to the ink drum axis, but diverges outwardly therefrom at each side of the =common-axial-planeof the drum and rotary support, whereby the roller is brought into operative relation, and remains in operative relation, to the ink drum through approximately twice the arc of travel that is spanned in ductor rollermechanisms of this type heretoforeknown.

3. The-combination according to claim 1, in which the radius of the said roller supporting arms is substantially equal to the roller radius, theshaftscarrying the said roller supportingarms are located at a distance from the rotary support axis substantially equal to the said supporting arm radius increased by the roller radius and the rotary support shaft radius, and the said spur gears have pitch radiiless than the said-roller supporting-arm-radii whereby the centers of the rollers trace a hypotrochoidal path which approaches a circular arc concentric to the ink drum axis, but diverges outwardly therefrom at each side of the common axial plane of the drum and rotary support, whereby the roller:is brought into operative relation, and remains in operative relation, to the ink drum through approximately 20 of the arc of'travel of the ductor roller relative to the ink drum.

4. The combination according to claim 1, in which the radius of the said roller supporting arms is substantially equal to the roller radius, the shafts carrying the said roller supporting arms are located at a distance from the rotary support'axis substantiallyequal to the said supporting arm radius increased by the roller radius and the rotary support shaft radius, and the said spur gears have pitch radii less than the said roller supporting arm radii whereby the centers of the rollers trace a hypotrochoidal path which approaches a circular-arc concentric to the-ink drum axis, but diverges 'outwardly, therefrom" at each side of the common axial planeof the drum and rotary support, whereby theroller isbrought into operative relation, and remainsin operative relation, to theink drum through a range between 10 and 40 of the arc of travel of the ductor roller relatively to the ink drum.

No references cited. 

